If you don't know sahti, you don't know beers. This primordial Finnish top-fermented beer is among the oldest still brewed beer types in the world. If there hadn't been a prohibition law in Finland from 1919 to 1932 it would also be the longest brewed beer type for sale ‒ officially. That crown now belongs to another fine beer, Belgian lambic, which also happens to have the probably closest resemblance of sahti.
Sahti's taste is soft, sweet and thick, often described as banana-like. Instead of hops it's flavoured with juniper. It doesn't bubble much and stores only a month at most the fridge. The old poems describe mash bushel being lifted on the roof for the thunder (=ukkonen) god Ukko water it and then fermented with the drool of a horny boar. And as you probably understand from this description sahti has a special place in certain pagan feasts.
At the moment I'm making my very first round of sahti for the most important holiday of the year, midsummer, the nightless day. This feast originally known as Vakkajuhla (= bushel feast) used to be celebrated with a big punch of friends by a lake to ask Ukko send rain for the harvest to grow. Christian invaders turned pretty much all the Finnish feasts to have Christian meanings but the only thing they managed to change in this one was its name: it's nowadays known as Juhannus which refers to John the Baptist. It still involves gatherings by lakes, drinking and eating, bonfires and fertility rites. I'll update this post after I've seen how my sahti turns out but I thought I'd post this plan already in the hope of inspiring the rest of you to try as well.
To be a purist you should keep in mind that:
1. Sahti doesn't contain hops. Instead it's usually flavoured with juniper (though I've heard some other herbs like heather or wild rosemary have been used as well).
2. Sahti is always made of barley malts. Some people also use rye or caramel malts but only small amounts for flavouring.
3. Don't use added sugar. All the sugar should come from the malts and sahti isn't supposed to sparkle either. You won't need sugar even in the bottling stage since it can't be stored long anyways. Besides, well cooked wort should already produce 10-11 % beer which in most beer types is more than enough to make it taste like alcohol and thus ruin its own taste.
4. Never let the mash temperature rise over 70°C or you'll get porridge. The wort shouldn't be cooked at all, only quickly sterilized at most.
5. The most common yeast used today is common baking yeast, not normal ale yeast. This gives sahti a distinct flavour. (Of course in the old times people just saved some yeast from every round for the next one. I wouldn't want to annoy an angry boar.)
6. Approximately, 1 kg of malts makes about 2 l of sahti. Yes, it's thick.
7. Sahti is served unfiltered. Actually the leftover yeast helps it last better.
8. Three most important things to remember are cleanliness, cleanliness and cleanliness. Sterilize all the tools you use, including your hands.
Of course, rules only exists to be broken. But if you do make exceptions to please your own taste then please don't call your beer sahti. You may feel it doesn't change that much if you use hops but names used very broadly cease to really mean anything. Here's what I did:
- 3 l sahti malts
- 3 dl rye malts
- 20 g juniper berries
- 7 l water
- 50 g baking yeast
Sterilize all your equipments. Put 3 l of water in a big pot and let it come to a boil. Add the malts. Keep stirring until you've got a porridge. Heat up until the temperature has reached 70°C and make sure it doesn't rise further. Simmer for an hour. Crush the juniper berries and throw them in. Simmer another three hours. Taste to make sure it's sweet enough. It's also desirable to measure the gravity at this point so it'll be easier to trace what went wrong.
Filter and pour into an air tight fermentation vessel (with airlock). Boil the rest of the water and pour in. When the temperature has dropped to about 20°C add the yeast, dissolved in a mug of lukewarm water. Let your sahti-to-be ferment in room temperature as long as it wants to. This should take about 3-5 days. Check the gravity again and bottle your sahti and store in cold for a week. Apparently, the bigger the barrel the longer the taste lasts. Don't leave room for oxygen. If you see a foam your sahti hasn't finished yet and shouldn't be drunk (unless you want stains in your underpants).
Ask your friends over to drink your sahti fresh! Here's a suggested drinking song as well.